Simple design of a novel broadband antenna: inverted microstrip patch loaded with a capacitive post

Much effort has been devoted to developing broadband and multiple frequency microstrip antennas. A novel technique to enhance the bandwidth of an inverted microstrip antenna is proposed. A simple design using a circular patch loaded with a capacitive post is described. The bandwidth characteristics of the antenna have been critically examined on the basis of experiments with a prototype antenna fabricated on RT- Duroid 5880 and measured on an HP 8720C network analyzer. Over 21 % impedance bandwidth for SWR<2 is evident from the experimental data. Measured radiation patterns are also presented. The new antenna design with a capacitively loaded inverted microstrip patch shows the possibility of achieving very large impedance bandwidth with satisfactory radiation patterns.